Depending on the processed material from each drill must be properly sharpened. To verify the correct angle will help a specially prepared square plate of copper or aluminium with a thickness of 1 mm.
To become operational protractor enough to cut it cut, as shown in the picture: a large cutout at an angle of 120 degrees, the other half is 60 degrees and the surviving corner of a square is 90.
Recommend to read
JOYSTICK WITH KEYBOARD?
The simpler the keyboard, the greater the number key (buttons) to press alternately or simultaneously to enter a particular character. For example, to write in a personal computer (PC)...
KIRISKA – NO DEFICIT!
Something I have done for drawings and diagrams, published in the journal under the heading "Club home of the masters". In one of the rooms was a note on the machine to edit used caps...